Self-closing containers



Sept. 3, 1963 e. DANELLI ETAL SELF-CEOSING CONTAINERS Filed Dec. 28, 1960 FIG. I

United States Patent SELF-CLOSHNG CONTAINERS Germano Danelli, Milan, and Sereno Jacopini, Novara,

Italy, assignors to Montecatini Societza Generale per llndustria Miner-aria e Chirnica, Milan, Italy Filed Dec. 28, 1960, Set. No. 78,905

Claims priority, application Italy Feb. 16, 1960 4 Claims. (Cl. 229-625) Our invention relates to a valve-type device for automatically closing flexible containers, to containers embodying said device, and to the said containers.

Various types of jute or paper bags have been provided with a tubular valve through which the bags are filled by means of a bag-filling machine. After the bags are filled, they are turned upside down. matic closing and sealing due to the pressure which the material in the bag exerts on the lower part of the valve. The valve is thus pushed and kept against the walls of the bag and prevents escape of material.

It has been attempted to manufacture big or medium size bags from plastic material that are to be just as suitable for easy and automatic bag filling on existent bagfilling machines as the known paper bags. However, the containers heretofore available require, independently of the used material, some rather complex valve structures consisting of a coupling or tubular body obtained by coupling of at least two pieces. These pieces are then fastened on the container with long and diflicult connections. Consequently, such a container, as a whole, is undesirably heavy.

It is an object of our invention to provide a container and valve device which greatly improves the known containers from the above-mentioned viewpoints and which also results in a substantially simplified manufacturing process.

We have discovered that valvular devices for bagfilling and closing purposes can be obtained from simple flat elements which are inserted into the containers mouth and are suitable for filling as well as for automatically closing the container while requiring less mate rial and less weight and affording a more favorable operation than the known containers of this general type.

According to a feature of our invention, the valvular device consists of a single element formed as a portion of a sheet, film, laminate or fabric strip. The material may be the same as, or different from, the one used for the walls of the container itself. One side of the valve element may be fastened on one side or edge of one container wall, and the other side of the valve member may be fastened to the other wall of the container. The valve side fastened to the first wall has a direction diiferent from the direction of the edge along which the same valve member is attached to the second wall of the container.

According to a more specific feature of the invention, a valve member consisting of a single piece or flat strip is fastened along its lower edge to a first wall of the container, along a vertical edge to the second wall of the container, and along its upper edge to both the walls, the fourth edge of the valve member remaining free.

While the fastening of the valve upper edge can be rectilinear, the fastening of its lower edge to the sheet of the container is preferably curvilinear, especially when the opening of the bag is not at the end of the laminate to which the valve member'is sealed along its lower horizontal edge, but is placed slightly at the interior of the external generatrix. In this case the resulting closure or seal shows a curve under the axis of the bag opening.

The new type of valve according to the invention reprocess of manufacturing H artisan Patented Sept. 3, 1963 quires modifying the manufacturing process of flexible containers with the result of minimizing the operations and total time required, thus reducing the cost of the container.

The process according to the invention is characterized by the faotthat the lower edge of the flat valvular memwise and below.

This causes auto- When plastics or other materials 'are used, which are not very resistant along the seams, it is convenient to strengthen the weak areas by applying adhesive tape during the sealing operation, preferably tapes ofpolyethyleneterephthalate.

The invention will be further described with reference to the attached drawings showing by way of example, but not for the purpose of limitation, a preferred embodiment of the invention.

In the drawings:

FIG. 1 shows in front view the basic element of the valve, removed from the container;

FIG. 2 shows in front view a wall of the container with the valve device arranged on its back;

FIG. 3 shows the second wall of the container according to FIG. 2, but turned relative to FIG. 2;

FIG. 4 is a perspective view of the upper part of the bag, comprising the valve according to the invention, and also shows in elevation the second wall of the container according to FIG. 3, the material of the second wall being assumed to be torn open along the lines marked X X -X to expose the lower welding seam of the valve;

FIG. 5 is a perspective view of the same upper part of the bag, but seen from the inside of the bag and from right to left, the walls of the bag being arranged as in FIG. 4 but with the two walls of the bag spaced apart from each other in the upper part and the valve welded by the process according to the present invention.

FIG. 6 shows the upper portion of another bag with V a modified valve device.

As shown in FIG. 1, the valve member V according to the invention consists of a single piece or fiat strip of a laminate, film or sheet with a lower edge B a lateral front edge B and upper edge B and a lateral rear edge L.

To facilitate explaining the invention, the container shown in FIG. 2 is supposed to be made of plastic material, without lateral sealing, and without cross sealing of the two laminates at the lower edges. The simplified bag is shown in frontal view from outside. Hence, only the frontal wall is visible. The valve member V is located behind the wall 1.

According to the invention, the single-piece valve member V is welded to the wall 1 only at the lower'edge B along the welding seam S shown by a broken line.

Since in FIG. 3, the container of FIG. 2 is turned 180, only the wall 2 is visible. The valve member V is welded to the inner face of wall 3, but only at the lateral force edge B along the welding seam S FIGS. 2 and 3 also show the welding, seams 5' along portion of the two walls between which the piece V is p 3 inserted. The valve member V extends over a desired width of the bag to the lateral valve edge L.

The front view shows the second wall 2 to which is welded the lateral fore edge B of valve member V along the welding seams S extending only in the direction of the height of the bag. a i

By virtue of the portion torn out along the line X 'X --X on wall 2 the member V can be seen welded to the laminate 1 at edge B of member Valong the welding seam S The invention will-be further understood if one imag-ines, according to FIG. 5, the upper part of the bag parted so that the lateral edges U (FIG. 2) of the bag appear spaced apart from each other, i.e., not yet welded, and without the seam S In FIG. 5, the valve member V is already fastened to walls 1 and 2. It will be seen that member V is welded to the wall 1 only at edge B along the seam S and that member V is welded to laminate 2 onlyat edge 2 along the seam Sgt.

The process of making the self-closing container above described is as follows. First the lower edge B of member V is fastened to the wall 1. Then the lateral fore edge B of member V is fastened to the edge of wall 2 along the height of said lwall. Thereafter the two laminates 1 and .2. and the valve member V are fastened together at the upper edge B along seam 8' this being i done in a single operation. Subsequently, the bottom and the two walls of the container are sealed along the two lateral edges U in the direction of the height, leaving only the month portion A open.

Regardless of whether the containers'or bags are made of plastic material, or of natural fiber (jute, paper, etc.), the operation for sealing sheets of fabric or paper along the lateral and cross edges is identical. In each case the process according to the invention has the advantage in substantially reducing the number of operations required to fasten the valve to the body of the bag, and in simplifying these operations, since the fastening of the valve on the inner face of the first wall occurs preferably when said wall is not yet connected with the second wall, while the fastening of the vertical edge of the valve to the second wall of the bag occurs preferably when the two walls are not yet welded or sewed on their lateral edges and on the upper and lower edges. This affords a greater the material, due to the fact that, when the bag is full or partially turned upside down, the filled-in material will rest upon the flaccid member V and press it against the wall 1, thus closing the opening A. The member thus acts as a trap or check valve.

- In the embodiment of FIG. 6, the valve member V is disposed as in FIG. 4, except that the opening A is not at the outer edge G of the container but is placed slightly inwardly away from the outer edge. The opening A is obtained by making a cut F in the wall l. This results in two lips H and H which are joined at their bottom by a circular opening R. Now the seam S 'is not rectilinear buthas a knee Q or curvilinear shape around the opening R. It has been ascertained that one of the weak points of a bag according to the invention is at the seam denoted by B in FIG. 4, but the provision of a lateral opening and a curved seam S disposed as in FIG. 6, prevent breaking along that seam.

The bags or other flexible containers according to the present invention are light in weight, easy to handle, can be quickly used with various types of bag-filling machines, reduce the time necessary for connection to the machines, can be given any desired small, medium or big size, and can be made of any desired material, such 4 l as jute, fabric, plastics, paper or the like. The material of the valve member V may be the same as, that of the container walls or may differ therefrom.

Particularly good results are obtained when using bags of plastic material, especially polyvinyl chloride, polyethylene, polypropylene, polyethylenterepht-halate, etc., or a combination of these materials. With such bags it is possible to use for the' valve member a material completely or partially different from the one .used for the walls. For instance, if the particular material to be filled into the bag requires the valve to be flexible or have strength and welding features diiferentfrom those of the resinous substance used for the walls, the valve member and/or the sealing borders may be made of a resin completely different from the one of the walls, or

from a resin which has been plasticized differently from dimensions of member V and of the walls may be given any desired ratio; and the walls 1 and 2 may be countersunk or shaped like a truncated cone.

Such and other variations are within reach of any one skilled in the art without departing from the essential features of our invention and are within the scope of the annexed claims.

We claim:

1. A bag having a front wall and a rear wall joined together along their common perimeter, one of said walls having a lateral slot shaped opening located near the top in parallel and inwardly spaced relation to one lateral edge of said wall, a valve member of flaccid material hav' ing generally rectangular shape with the long edges thereof extending parallel to the top of sai-d walls, said member extending over part of the width of said bag, one of said long edges of said member being sealed together with said two bag walls along s-aid top, the other long edge being sealed together with only one of said two walls, tone of the short edges of said member extending along saidlateral opening and being sealed together with only one of said walls, the fourth edge of said member remaining unattached, said opening having a round extension at its bottom, and said other long edge of said member forming together with said one bag wall which has said slot shaped opening a seam of curved configuration having a curved portion extending around part of 'said roun extension. l

2. A bag having a front wall and a rear wall joined together along their common perimeter, one of said walls having a lateral slot shaped opening located near the top in'parallel inwardly spaced relation to one lateral edge of said wall, a valve member of flaccid material having generally rectangular shape with thelong edges thereof extending parallel to the top of said walls, said member extending over part of the width of said bag, one of said long edges of said member being sealed together with said;

portion extending around the lower end of said opening.

3. A bag-like flexible container having a front wall and a rear wall of flaccid and weldable plastic joined together in face-t-o-face relation along the vertical and horizontal edges thereof, means forming a filling opening between a said two walls along one vertical edge near the top of said container, a substantially rectangular valve member inside said container and consisting of a single continuous sheet of flaccid and Weldable plastic, said member being Welded to one of said walls along two generally parallel edges of the member and having another edge welded to only the other of said walls along said filling opening, the fourth edge of said member remaining free and unattached inside said container, whereby While the container is 'being filled with fiowable material the latter will enter the container through said lateral opening and pass between said top and bottom edges of said sheet and beyond said free edge of the sheet to drop into the container, and when said container is substantially filled and inverted, the flow able material in the bag will press said free edge of said sheet against the wall to which said bottom edge is attached to thereby prevent discharge past said free edge.

47 In a flexible container having a front Wall and a rear Wall, a self-closing valve device comprising "a single continuous sheet of flaccid material extending inside said container and partially across the container at one end thereof and attached to both of said walls, said sheet having three generally linear areas of attachment, the first of said attaching areas being coextensive with a longitudinal edge of said sheet and sealingly joining said longitudinal edge with both said walls, the second of said areas extending transversely to said first attaching area and joining said sheet to only one of said walls, and the third of said areas being spaced from and extending generally in the same direction as said first attaching area and joining said sheet to only the other of said walls, said container forming a filling opening extending along said second attaching area and the edge of said sheet furthest from said second attaching area being hee and unattached and terminating inside the container, whereby While the container is being filled with fiowable material the latter will enter the container through said filling opening and pass between said first and third attaching areas and beyond said free edge of the sheet and drop into the container, and when said container is substantially filled, the flowable material in the bag will press said free edge of said sheet flush against the Wall common to said third attaching area to thereby prevent discharge past said free edge.

References Cited in the file of this patent UNITED STATES PATENTS 2,696,342 Toborg Dec. 7, 1954 2,697,531 Hood Dec. 21, 1954 2,870,954 Kulesza Jan. 27, 1959 3,003,682 Mattson Oct. 10, 1961 

1. A BAG HAVING A FRONT WALL AND A REAR WALL JOINED TOGETHER ALONG THEIR COMMON PERIMETER, ONE OF SAID WALLS HAVING A LATERAL SLOT SHAPED OPENING LOCATED NEAR THE TOP IN PARALLEL AND INWARDLY SPACED RELATION TO ONE LATERAL EDGE OF SAID WALL, A VALVE MEMBER OF FLACCID MATERIAL HAVING GENERALLY RECTANGULAR SHAPE WITH THE LONG EDGES THEREOF EXTENDING PARALLEL TO THE TOP OF SAID WALLS, SAID MEMBER EXTENDING OVER PART OF THE WIDTH OF SAID BAG, ONE OF SAID LONG EDGES OF SAID MEMBER BEING SEALED TOGETHER WITH SAID TWO BAG WALLS ALONG SAID TOP, THE OTHER LONG EDGE BEING SEALED TOGETHER WITH ONLY ONE OF SAID TWO WALLS, ONE OF THE SHORT EDGES OF SAID MEMBER EXTENDING ALONG SAID LATERAL OPENING AND BEING SEALED TOGETHER WITH ONLY ONE OF SAID WALLS, THE FOURTH EDGE OF SAID MEMBER REMAINING UNATTACHED, SAID OPENING HAVING A ROUND EXTENSION AT ITS BOTTOM, AND SAID OTHER LONG EDGE OF SAID MEMBER FORMING TOGETHER WITH SAID ONE BAG WALL WHICH HAS SAID SLOT SHAPED OPENING A SEAM OF CURVED CONFIGURATION HAVING A CURVED PORTION EXTENDING AROUND PART OF SAID ROUND EXTENSION. 